The invention of the laser and the subsequent development of the high energy/power laser (P &gt; 200 kw) focused attention on the potential of the high energy/power laser in the U.S. Army roles and missions in defense of the United States. In order to evaluate this potential it is necessary to conduct experiments on the characteristic effects of propagation, materials damage and target vulnerability as a function of energy density and total laser beam power.
However, the highly intense laser beam oversaturated and destroyed known energy detectors and power meters with the exception of large heat sink spherical calorimeter which totally blocked the beam. When the beam energy was spread over a larger area the ratio of the area of the beam to the detector area was so large that accurate and reliable power measurements could not be made due to inhomogeneties in the beam. The power could be measured only by intercepting the total beam in a large calorimeter or the phenomenological effects produced without the measurement of energy/power. Therefore, the relationship between power and effects could not be accurately established since measurements of both factors could not be made simultaneously.
This condition required a device which would accurately sample and measure the beam power without blocking or unduly perturbing the beam for phenomenological effects purposes. The device of the present invention accurately and reliably samples the beam energy at an acceptable frequency and low amplitude without effecting the beam characteristics for further experimental use. This feature is unique in high energy laser power meters. All known energy measuring devices are for very low level energy or block a high energy beam completely.